1. Field of the Invention
The present invention relates to a blasting apparatus, and more particularly, relates to a blasting apparatus for an outer surface of a pipe, which ejects a blast material to an outer surface of a pipe and grinds the outer surface of the pipe to perform surface preparation.
2. Description of the Related Art
For example, a vent pipe (piping) placed inside a suppression chamber, which is a part of a nuclear reactor containment facility of an atomic power plant, has its outer peripheral surface and inner peripheral surface coated by recoating it with a plurality of coating materials excellent in corrosion resistance, decontaminability and the like. The repainting construction is carried out with about 10 years after the start of operation as a guide, and as a pre-construction of the repainting construction, grinding and decontaminating operations of grinding the coating film including radioactive substances on the outer peripheral surface and the inner peripheral surface and roughening the coated surface to perform surface preparation are performed.
Conventionally, no apparatus for grinding and decontaminating the inner peripheral surface of a vent pipe is available, and grinding and decontaminating of only the outer peripheral surface is carried out by a blasting technique. The blasting technique is a technique of causing a blast material such as sand, and steel grit ejected by high speed air to collide against a substance to be treated, grinding the surface of the substance to be treated with the impact force to roughen the surface (for example, see Japanese Patent Application Laid-Open No. 9-109029).